JPS63156062A - High permittivity ceramic composition and manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention relates to a high dielectric constant ceramic composition and a method for producing the same.
In particular, the present invention relates to a high dielectric constant ceramic composition whose dielectric constant changes little over a wide temperature range, and a method for producing the same.

(Prior Art) Electrical properties required for dielectric materials include dielectric constant, temperature coefficient of dielectric constant, dielectric loss, dependence of dielectric constant on electric field, and capacitance-resistance product.

In particular, the capacitance resistance M (CR value) needs to take a sufficiently high value, and must be 500MΩ・μF or more at room temperature according to the EIAJ (Electronic Industries Association of Japan) standard for multilayer ceramic capacitors (chip type) for electronic equipment RC-3698B. stipulated. Furthermore, in order to be able to use it under even more severe conditions, high temperature (for example, 125
The CR value is determined in °C. ), it is required to maintain a high capacitance-resistance product.

In addition, there are cases where stable temperature characteristics are particularly required over a wide temperature range.1 For example, the EIA (Electronic Industries Association) standard X7R characteristics have a capacitance change of ±15°C in the temperature range of -55°C to +125°C. % or less.

Furthermore, when considering a laminated type element, since the electrode layer and the dielectric layer are fired integrally, it is necessary to use an electrode material that is stable even at the firing temperature of the dielectric material.

Therefore, if the firing temperature of the dielectric material is high, expensive materials such as Pt and Pd must be used.In order to use stable materials such as Ag, firing at a low temperature of, for example, 1100°C or less is possible. This is required.

Conventionally known high dielectric constant ceramic compositions include barium titanate as a base and solid solutions of stannate, zirconate, titanate, etc. therein.

However, the firing temperature of barium titanate-based materials is 130°C.
The temperature is high, about 0 to 1400° C., and expensive materials such as platinum and palladium that can be dissolved at high temperatures must be used as electrode materials, which causes high costs.

In order to solve the problems of this barium titanate system.

Various compositions have been studied. For example, those mainly composed of iron and lead niobate (Japanese Patent Application Laid-Open No. 57-57204),
Mainly composed of magnesium and lead niobate (Japanese Unexamined Patent Application Publication No. 1989-1989)
5-51759), those mainly composed of magnesium/lead tungstate (JP-A-55-144609), those mainly composed of magnesium/iron/lead tungstate (
JP-A No. 58-217462), etc.

However, the dielectric constant is high, and the temperature change is -5
A high dielectric constant ceramic composition that is small over a wide temperature range of 5°C to +125°C, has excellent electrical properties such as high insulation resistance, and can be sintered at low temperatures has not been obtained. is the current situation.

On the other hand, research has also been carried out to obtain flat temperature characteristics by mixing compositions with different temperature characteristics of dielectric constants.
ali)Oi-Pb(Mnxzzlltzi)Ox system.

PbCMg1tsNb*ts)Os-PbTiOs-P
There is a disclosure of a mixture of the bCFexi3'l,ts)Oz system. However, T, C, and C are large and the temperature characteristics are not sufficient, and JJAP, voQ, 24 (1
985) Supplement24-2. pp, 42
7-420 has PbCF@ztsNb,tx)Oz-P
bCF6ttsW1 c) Although there is a disclosure regarding the mixture of Os, there is no consideration of CR value, which is important as a capacitor material, and T, C, and C are large, and the temperature characteristics are not sufficient.

(Problem that the invention attempts to solve) The present invention has been made in consideration of the above points.

It is an object of the present invention to provide a method for manufacturing a high-permittivity ceramic composition that has a high dielectric constant and insulation resistance, has a small temperature change in the dielectric constant, and can be sintered at a low temperature.

[Structure of the invention]

(Means for Solving the Problems) The present invention is based on the general formula (1-XXhea-^policyb) (CZnuJthis)1-c-ticK&is Nb
, /3) cTia)Os ・xBaTiOs When expressed as 0 ≦ a ≦ 0.35 0 ≦ b ≦ 0.35 0.01 ≦ a + b ≦ 0.350 < c
≦ 0.9 0dd ≦ 0.5 0 < c+d < 1.0 0.3 ≦ X ≦ 0.65. It can be obtained by using at least barium titanate powder.

(Function) Generally, porcelain compositions contain Pb, Ba, S as starting materials.
r.

Oxides such as Zn, Mg, Nb, and Ti, salts such as carbonates and oxalates that become oxides upon firing, hydroxides, organic compounds, etc. are weighed out in a predetermined proportion, mixed thoroughly, and then calcined. After that, the calcined product is pulverized to produce a raw material powder. By molding such raw material powder into a desired shape and firing it, a ceramic with a high dielectric constant is obtained.8 In the present invention, instead of the general method as described above, BaTi0. A raw material containing at least powder and other ingredients are mixed and fired. In the high dielectric constant ceramic composition produced by such a method, the range of temperature change in dielectric constant is further reduced.

That is, the manufacturing method of the present invention includes the following steps. Among the starting materials, BaTi0. 8a, which is a component of BaTi0. Prepared to have the chemical formula of 1000 ~
Calcinate at 1350℃. At this time, it does not matter if the stoichiometric ratio deviates to some extent. This calcined powder and other starting materials are weighed at a predetermined ratio and thoroughly mixed and pulverized. In this case BaTi
0. It is preferable to use a resin-coated ball or the like to avoid crushing the powder too much. In this case, other starting materials mainly consisting of PB (which may also contain Ba and Ti) are mixed separately and It is desirable to calcinate at around ℃.

Also, BaTi0. It does not matter if the powder of the constituent components contains a small amount of other elements.

After thoroughly mixing and pulverizing the powder and molding it into the desired shape,
By firing, a high dielectric constant ceramic composition is obtained.

As for the mixing and grinding balls, it is preferable to use balls with high hardness and high toughness, such as partially stabilized zirconia balls, in order to prevent the mixing of impurities. When mixing the first component mainly consisting of BaTi0. It is preferable to use a resin-coated ball or the like to avoid crushing too much.

The porcelain composition thus obtained is basically BaTi.
0. The result is a mixed sintered body of the main first component and the second component having a perovskite structure containing pb as a constituent element.
BaTi0. has a single Curie point near 125°C, and the second
Good temperature characteristics can be obtained by the synergistic effect with the components. Furthermore, the dielectric constant and CR value are high, making it suitable for use in capacitors. During sintering, BaTi0. If the powder is too fine, the first component and the second component will diffuse too much, making it difficult to obtain the effect of improving temperature characteristics. In addition, if the size is too large, the number of bores and cracks in the sintered body will increase significantly, resulting in a decrease in CR value and mechanical strength, which will cause compositional fluctuations, especially when creating a laminated type element. This causes a decrease in yield by 1.

Therefore, more than 50 wt% of the BaTi0i powder used is 0.
．． 7-3tm, more preferably 0.8-2. It is preferable to use particles with a particle size of It can be achieved. Note that the Curie point as the second component mentioned above is 12
The temperature should be set at 5° C. or lower, roughly between room temperature and around 80° C. considering the interaction between the first and second components. Also, when lowering the firing temperature (for example, 1100°C or lower) is important, it is preferable to use a temperature lower than room temperature. Ba in powder
It is possible to replace a part of Ti with Sr, Ca, or Ce, or to replace a part of Ti with Zr or Sn.

Next, the composition of the present invention will be explained. The composition of the present invention is expressed by the general formula (%). When expressed in the general formula, the substituting elements Ba and Sr of pb can form a perovskite structure with a small amount of substitution. , (a + b) is less than 0.01, it is difficult to form a perovskite structure, and the dielectric constant decreases.
Also, if (a + b) exceeds 0.35, the firing temperature will become high. * Regarding Q g d, if it is outside this range, the temperature change in the dielectric constant will become large, and (Zn1 ha Nb * zs ) It is better to contain a certain amount of components, and c+d≦0.9 is preferable.

Also, if X exceeds 0.65, the firing temperature will become high, and if it is less than 0.3, the temperature change in the dielectric constant will become large.In particular, if the temperature change is to be carried out heavily, 0.5 x ≦0.
65. If the firing temperature is important, 0.3≦x≦0.
5 is preferred.

When ap by Og d, A porcelain composition that can be bonded is obtained.

The composition of the present invention has the following composition: (1-X) (Pl)1-a-bBaaSrb) ((Z
nx tzR)z ts )1-C4(Mg, is N
BI ts)cTld)03”xBaTio.

However, it does not matter if the ratio deviates slightly from the stoichiometric ratio, when converted to oxide.

Pb0 26.49~53.33%+1%Ba0 15
．． 01-39.48 wt%SrO0.00-9.71
wt% Zn0 0.49-6.86 wt%MgOO,00
~3.14 tzt% Nb, 0. 8.00-23.03 wt%Tie,
It becomes 7.81-23.641t%. Preferably, PbO26,49-52.58 wt% BaO15,0
1~39.07wt%SrOO,00~9.57w
t% Zn0 0.49-6.86 wt%MgOO,00
~3.14 wt% Nb, 0. 8.00-23.03 wt%Tie,
It is 7.81 to 23.39 wt%.

Among these, those in which part of T1 is replaced with Zr have a small decrease in dielectric constant around the Curie point.

Are suitable. Therefore, BaTi0. Ba instead of
(Ti, -5Zra)Oa may be used, however, in this case, the amount of Zr substitution is at most 6 mol! %(0≦e≦0
．． 06). This is because if the temperature exceeds this value, T, C, and C on the high temperature side will become large when porcelain made of a mixed sintered body is formed.

Also, when converted to oxide, Pb0 19.28 to 40.35% + 1% Ba0 26
．． 73-46.73 wt%Sr0 0.00-7.
15 wt%Zn0 0.36-5.11 wt%M
gOO, 00-2.33 wt% Nb, 0. 5.84-17.11 wt%? 10.
13.08-26.64 wt% ZrO, 0.00-1
．． It becomes 93 wt%.

Also, 1. impurities within a range that does not impair the effects of the present invention.

It is okay to include additives, etc. For example, Ca0g La
20xtMnO, Cod, Nip, Sb, O,, S
Transition metals such as in, ZrO, etc.

Examples include lanthanide elements. However, the content of these additives is about lwt% at most.

When manufacturing a laminated type element, a binder, a solvent, etc. are added to the raw material powder or mixed and pulverized powder to form a slurry, a green sheet is formed, internal electrodes are printed on this green sheet, and then the predetermined Manufactured by laminating and crimping several sheets and firing them.

At this time, since the dielectric material of the present invention can be sintered at a low temperature, an inexpensive material mainly composed of Ag, for example, can be used as the internal electrode material.

Furthermore, since it can be fired at such a low temperature, it is also effective as a material for thick film dielectric pastes printed and fired on circuit boards and the like.

Such a ceramic composition of the present invention has a high dielectric constant and good temperature characteristics. In addition, the CR value is large, particularly sufficient even at high temperatures, and has excellent reliability at high temperatures.

Furthermore, the dielectric constant bias electric field dependence is also excellent.

Even at 2KV/is, it is possible to obtain a material of about 10% or less. Therefore, it is effective as a material for high pressure.

Furthermore, it has low dielectric loss and is effective for AC and high frequency applications.

Furthermore, as described above, since the dielectric constant has excellent temperature characteristics, even when applied to an electrostrictive element, an element with small humidity change in displacement can be obtained.

Furthermore, since the grain size during firing is made uniform to 1 to 3-3, it has excellent pressure resistance.

Although the electrical properties have been described above, the mechanical strength is also sufficiently excellent.

(Example) The present invention will be explained in detail below.

Among the starting materials, BaTi0. BaC0 and TiO□, which are the components of
The mixture was calcined at 00 to 1350°C and further ground using a ball mill.

In this case, by changing the grinding conditions of the ball mill, the obtained B
aTi0. The particle size of the powder was controlled. Note that the particle size was determined by measuring the average particle size using the Blaine method.

On the other hand, BaTi0. Pb, Ba, Sr, Z other than
Oxides or carbonates such as n, Tl, and Mg were mixed separately in a ball mill or the like, calcined at 700 to 900°C, and pulverized.

Next, these calcined bodies were weighed to a predetermined ratio and mixed using a pot. After drying.

A binder was added, granulated, and pressed to form a disk-shaped element body with a diameter of 17 m and a thickness of about 2 sides.

This element body was sintered in air at 1000-1100°C for 2 hours, silver electrodes were baked on the amphib side, and various properties were measured.

Dielectric loss, capacitance is I KHz, I Vrms, 25
These are the values measured by a digital LCR meter under the conditions of ℃, and the dielectric constant was calculated from this value. Also, the insulation resistance is 1
It was calculated from the value measured using an insulation resistance meter after applying a voltage of 00V for 2 minutes. Note that the temperature characteristic of the dielectric constant is 2
Based on the value of 5°C, it was expressed as the maximum value of the change width in the temperature range of -55°C to +125°C. Capacitance resistance product (CR
The value) was determined from (specific electrical constant) x (insulation resistance) x (vacuum permittivity) at 25°C and 125°C. The insulation resistance was measured in silicone oil to eliminate the effect of moisture in the air. 12. For comparison, an example using [1aTiO, which has a small particle size] is shown in Table 1 as Reference Example 1. Furthermore, for comparison, an example using [1aTiO, which has a large particle size] is shown in Table 1 as Reference Example 2. Shown below.

Also, replace pure aTiO with one cucumber for 10~
(Ba, , , Sr, , , )Ti lowered by 30°C
The results using O2 are shown in Example 6 in Table 1.

(Left below) Also, instead of pure aTiO3, add one cucumber for 10~
Using Ba (TiL-eZra)Os lowered by 30°C, the general formula % formula %) ((乃, M width / 3) 1 E (gourd / 3-is ). To 1 phrase - (Ti, spear.凰 or (Pb(i-)D (4-a-b>Ba(t-X)a+
X5r(x-x+b)((ZrhtsNb*ts)(
1-x) tz-c-a>CMktsNb2iz)<x-
x>-c, Ti<x-x>d+xt1-eJXx*e)
The results obtained for the composition represented by Os are shown in Examples 13 to 15 and Reference Example 5 in Table 2.

(Left below) As is clear from Table 1, the ceramic composition of the present invention has a high dielectric constant (K=4000 or more) and good temperature characteristics (-55
+22.℃~+125℃. -33% or less).

In addition, the CR value is large at over 50,000F (25℃),
In particular, it has a resistance of 1000ΩF or more even at 125°C, and has excellent reliability at high temperatures.

Reference Example 1 is an example using aTiO having a small particle size, but it shows that the dielectric constant value is small and the temperature change width is also large.

Further, although Reference Example 2 is an example using aTiO3 having a large particle size, the CR value is significantly lowered.

Further, in Example 6, BaTi0. Instead of , Ba, , , Sr, , where one point of Curi was moved to around 100℃
, Tie, and excellent characteristics were obtained in this case as well. BaTi0. In addition to replacing Sr with Ca, Ce, and Zr.

Substitute with Sn etc. and heat one cucumber at 10-30℃
Similar results were obtained using the transferred components.

Furthermore, as is clear from Tables 1 and 2, Example 7
-15 has a high dielectric constant (K = 2300 or more) and good temperature characteristics (within ±10% at -55°C to +125°C), and in particular, BaTi0. Ba(Ti
,,5sZro,. )0. Examples 13 to 15 using
±7.5 in the temperature range from -55℃ to +125℃
% or less was obtained. Also, CR
The value is also large, over 8000ΩF (25℃), especially 125
It has a resistance of more than 2500 ΩF even at ℃, and has excellent reliability at high temperatures.

In reference example 5, a part of T1 is replaced with BaTiO3 by Zr.
2moQ% substituted Ba (Tie, *, zro, za)
Although it uses Os, the range of change in permittivity on the high temperature side is ±
It has exceeded 10%. Therefore, the amount of Zr substitution is preferably within the range of the present invention. In addition, [3aTiOs is Z
In addition to replacing with r, some of Ti may be replaced with Sn,
Similar results were also obtained using components in which a part of Ba was replaced with Sr, Ca, or Co, and the Curie point was shifted by 10 to 30°C.

Next, an example will be described in which a multilayer ceramic capacitor was fabricated using a composition in which 0.25 moQ% of MnO and CoO were added to Example 3.

First, BaTi0. and other calcined powders were weighed at a predetermined ratio, mixed well, and an organic solvent was added to form a slurry, after which a 30 μs green sheet was created using a doctor blade type caster. A 70Ag/30Pd electrode paste was printed on this green sheet in a predetermined pattern, and 20 sheets having such an electrode pattern were laminated and pressure-bonded. Thereafter, it was cut into a predetermined shape, degreased, and fired at 1080° C. for 2 hours. After sintering, Ag paste was baked as an external electrode to produce a multilayer ceramic capacitor. Its electrical characteristics are shown in Table 3.

Table 3 The dielectric constant of the obtained multilayer ceramic capacitor is approximately 570
0, and as shown in Table 3, it can be seen that each property is sufficiently excellent. Especially when the temperature is -55℃~
It is within ±22% at +125°C and satisfies the EIA X7S characteristics.

Next, 0.1 moQ% MnO was added to Example 15.
An example will be described in which a multilayer ceramic capacitor was manufactured using a composition containing additives and Coo.

First, BaTia, 5sZro, which has such a composition
, ashy and other calcined powders are weighed in a predetermined ratio, mixed well, and an organic solvent is added to form a slurry.

A 30-green sheet was prepared using a doctor blade type caster. 70Pd on this green sheet
/30Ag electrode paste is printed in a predetermined pattern,
Twenty layers of sheets having such electrode patterns were laminated and pressure-bonded. After that, cut it into a predetermined shape, degrease it,
Firing was performed at 1220° C. for 2 hours. After sintering, paste A was baked as an external electrode to produce a multilayer ceramic capacitor. Its electrical characteristics are shown in Table 4.

Table 4 The dielectric constant of the obtained multilayer ceramic capacitor is approximately 270
0, and as shown in Table 2, it can be seen that each property is sufficiently excellent. In particular, the temperature characteristics are -55℃~+
It is within ±7.5% at 125° C. and satisfies the EIA X7F characteristics.

As described above, the method for producing a high-permittivity ceramic composition according to the present invention provides a high-permittivity ceramic composition that has a large dielectric constant and has excellent various properties such as a small change in dielectric constant over a wide temperature range. This method is particularly effective as a manufacturing method for multilayer ceramic capacitors. In addition, in the manufacturing method of the present invention, zinc lead niobate and barium titanate were used as main ingredients, but the same effects as the present invention may be obtained by using other ingredients in place of these. be.

〔Effect of the invention〕

As explained above, according to the ceramic composition and manufacturing method of the present invention, it is possible to obtain a high dielectric constant ceramic composition that has a high dielectric constant, high insulation resistance, and excellent temperature characteristics. In particular, it is possible to obtain ceramics with significantly improved temperature characteristics over a wide temperature range, so it is suitable for application to multilayer ceramic elements such as multilayer ceramic capacitors and multilayer ceramic displacement elements.

Agent: Patent Attorney Noriyuki Chika Same as Mitsuyuki Matsuyama

Claims (1)

[Claims] (1) General formula (1-x) (Pb_1_-_a_-_bBa_aSr_
b) {(Zn_1_/_3Nb_2_/_3)_1_-
_c_-_d(Mg_1_/_3Nb_2_/_3)_
When expressed as cTi_d}O_3・xBaTiO_3, 0≦a≦0.35 0≦b≦0.35 0.01≦a+b≦0.35 0<c≦0.9 0<d≦0.5 0<c+d A high dielectric constant ceramic composition that satisfies <1.0 0.3≦x≦0.65. (2) The high dielectric constant ceramic composition according to claim 1, characterized in that 0.3≦x≦0.5. (3) The high dielectric constant ceramic composition according to claim 1, characterized in that 0.5<x≦0.65. (4) The high dielectric constant ceramic composition according to claim 1, characterized in that 0<c+d≦0.9. (5) The high dielectric constant ceramic composition according to claim 1, wherein a part of Ti in BaTiO_3 is replaced with Zr. (6) General formula (1-x) (Pb_1_-_a_-_bBa_aSr_
b) {(Zn_1_/_3Nb_2_/_3)_1_-
_c_-_d(Mg_1_/_3Nb_2_/_3)_
cTi_d}O_3・xBa(Ti_1_−_eZr_
e) When expressed as O_3, 0≦a≦0.35 0≦b≦0.35 0.01≦a+b≦0.35 0<c≦0.9 0<d≦0.5 0<e≦0 .06 0.3≦x≦0.65 0<c+d<1.0 The high dielectric constant ceramic composition according to claim 5. (7) The high dielectric constant ceramic composition according to claim 6, characterized in that 0.3≦x≦0.5. (8) The high dielectric constant ceramic composition according to claim 6, characterized in that 0.5<x≦0.65. (9) The high dielectric constant ceramic composition according to claim 6, characterized in that 0<c+d≦0.9. (10) General formula (1-x) (Pb_1_-_a_-_bBa_aSr_
b) {(Zn_1_/_3Nb_2_/_3)_1_-
_c_-_d(Mg_1_/_3Nb_2_/_3)_
When expressed as cTi_d}O_3・xBaTiO_3, 0≦a≦0.35 0≦b≦0.35 0.01≦a+b≦0.35 0<c≦0.9 0<d≦0.5 0<c+d <1.0 0.3≦x≦0.65 A method for producing a high permittivity ceramic composition, characterized in that at least barium titanate powder is used as a raw material when producing a high permittivity ceramic composition satisfying 0.3≦x≦0.65. . (11) 50wt% or more of barium titanate powder has a particle size of 0
．． 11. The method for producing a high dielectric constant ceramic composition according to claim 10, wherein the diameter is 7 to 3 μm. (12) The method for producing a high dielectric constant ceramic composition according to claim 10, characterized in that 0.3≦x≦0.5. (13) The method for producing a high dielectric constant ceramic composition according to claim 10, characterized in that 0.5<x≦0.65. (14) The method for producing a high dielectric constant ceramic composition according to claim 10, characterized in that 0<c+d≦0.9. (15) A method for producing a high dielectric constant ceramic composition according to claim 10, characterized in that a part of Ti in BaTiO_3 is replaced with Zr. (16) General formula (1-x) (Pb_1_-_a_-_bBa_aSr_
b) {(Zn_1_/_3Nb_2_/_3)_1_-
_c_-_d(Mg_1_/_3Nb_2_/_3)_
cTi_d}O_3・xBa(Ti_1_−_eZr_
e) When expressed as O_3, 0≦a≦0.35 0≦b≦0.35 0.01≦a+b≦0.35 0<c≦0.9 0<d≦0.5 0<e≦0 .06 0.3≦x≦0.65 The method for producing a high dielectric constant ceramic composition according to claim 14, characterized in that 0.3≦x≦0.65 is satisfied. (17) The method for producing a high dielectric constant ceramic composition according to claim 15, characterized in that 0.3≦x≦0.5. (18) The method for producing a high dielectric constant ceramic composition according to claim 15, characterized in that 0.5<x≦0.65. (19) The method for producing a high dielectric constant ceramic composition according to claim 15, characterized in that 0<c+d≦0.9.